1. Field of The Invention
The present invention pertains to power transmission apparatus for transmitting mechanical power. More particularly, the present invention relates to multiple speed ratio power transmission apparatus, such as the power transmissions used on motor vehicles.
2. Description of the Relevant Art
There are many known transmissions for transmitting mechanical power, including many transmissions which can provide different speed ratios between an input motion and an output motion. For example, all motor vehicles are provided with such multiple speed ratio transmissions for transmitting rotative power from an engine to a vehicle's drive wheels. In such known transmission apparatus a provision for obtaining a plurality of driving speed ratios is normally made through selecting a different torque transmitting path for each speed ratio. Further, an execution of selecting the various speed ratios is accomplished through an engaging-disengaging process involving some type of clutch mechanism such as power friction clutches, synchronizers, manual couplers. As will be understood, the complexity of known multiple speed transmission apparatus is directly related to the number of speed ratios desired.
Additionally, there are known constant-variable transmissions (CVTs) which have a single torque transmitting path, but the known CVTs also include friction elements (such as CVT pulleys) for transferring torque.
The present invention has been developed to provide a multiple speed ratio transmission device which, in contrast to the known transmission devices, is relatively simple and compact.